[debugger] simplify debug stepping.

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 5947582c441f3f45e7e97df60b1932482bc2e53d..a90d544b54785d544b830e82f2e48bcd62ee6194 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -1065,8 +1065,8 @@ class ExternalReference BASE_EMBEDDED {
 
   Address address() const { return reinterpret_cast<Address>(address_); }
 
-  // Used to check if single stepping is enabled in generated code.
-  static ExternalReference debug_step_in_enabled_address(Isolate* isolate);
+  // Used to read out the last step action of the debugger.
+  static ExternalReference debug_last_step_action_address(Isolate* isolate);
 
   // Used to check for suspended generator, used for stepping across await call.
   static ExternalReference debug_suspended_generator_address(Isolate* isolate);